1. Field of the Invention
This invention relates generally to the control of the execution of instructions by a data processing system and more particularly to a data processing system capable of sharing a plurality of operating systems.
2. Description of the Related Art
It is known in the related art to provide a data processing system capable of execution of an instruction set under control of a single operating system. Each operating system has an interior decor, including a distinctive address formation and instruction processing characteristics, that prohibit easy portability of operating systems. In order to utilize a plurality of operating systems, it has been necessary to alter the operating systems or add additional apparatus to operate additional apparatus. In addition, it is frequently necessary to reinitialize the data processing system each time a different operating system was activated. Frequently, improvements in operating systems require a change in apparatus and can cause problems in data systems. In addition, fault procedures residing in the memory unit have the characteristics of a specialized operating system.
Therefore, the need has existed for a data processing system capable of sharing a plurality of operating systems.